Dustproof mask



FIG. 1 is a front, right side, and top isometric view of a dustproof mask showing the new design.

FIG. 2 is a bottom plan view of the dustproof mask.

FIG. 3 is a top plan view.

FIG. 4 is a right side elevation view. The left-side elevation view is a mirror image of this view.

FIG. 5 is a front elevation view.

FIG. 6 is a back elevation view; and,

FIG. 7 is a front, right side, and top isometric view of the dustproof mask from an angle that differs from the angle used in FIG. 1. 

CLAIM The ornamental design for a dustproof mask, as shown and described. 